HOT SPRINGS in ICELAND. 133 



bright, and the veins were marked with more delicacy. The 

 tranfition likewife from one fubftance into the other, was more 

 evident and fatisfactory. 



To the depth of a few inches, the ground confided of loofe 

 lavas, broken and pounded together, of blue, red and yellow 

 colours. The blue lava was hardeft ; and feveral pieces of it 

 remained firm and unaltered, while the reft were reduced to a 

 dull. The colours became brighter as the decompofition of the 

 fubftances advanced, and they were changed at the depth of 

 nine or ten inches into a clay ; excepting, however, the pieces 

 of dark blue lava, which ftill retained fufficient hardnefs to re- 

 lift the preflure of the finger. Round thefe, (which appeared 

 infulated in the midft of the red and yellow clay), feveral veins 

 or circles were formed of various fhades and colours. A few 

 inches deeper, thefe alfo became part of the clay, but ftill ap- 

 pearing diftinct, by their circles, from the furrounding mafs. 

 The whole of this variegated fubftance refted on a thick bed of 

 dark blue clay, which had evidently been formed in the fame 

 manner from fome large fragment of blue lava, or ftratum of 

 it, broken into pieces. 



The refemblance of thefe clays to jafper is fo ftriking to the 

 eye, that I cannot forbear believing their origin to be fimilar, at 

 leaft, that fome circumftances in the formation of each are the 

 fame. You will fay, with reafon, that the difference, notwith- 

 standing the apparent fimilitude, is in reality very wide ; that 

 thefe clays, before they can be converted into jafpers, require 

 to be confolidated, and impregnated with a confiderable propor- 

 tion of filiceous earth. It is fomething, however, to have de- 

 tected nature in the act of forming, in any fubftance, the veins 

 and figures common to marbles and jafpers. What ftill re- 

 mains of the procefs, after thus much of it has been traced, 

 may not long continue unknown ', and in Iceland, probably 

 fooner than elfewhere, will be difcovered beds of clay, like this, 

 hardening into ftone* either by the effect of fubterraneous heat 



